Fig. 4

Record of alewife presence at and movement between locations in Minas Basin. The number of tagged individuals detected at each location is shown, with the total number of presence events in brackets. Blue arrows indicate movement from one location to another within a 6.2-h time span. Pink arrows indicate movement within a 24.8-h time span. The notation nf:nb associated with each arrow indicates the number of movements in the arrow direction (nf) and in the opposite direction (nb). Inset illustrates flood–ebb tidal currents